Astronomy:2MASS J05325346+8246465

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Short description: Star in the constellation Camelopardalis

Coordinates: Sky map 05h 32m 53.46s, +82° 46′ 46.5″

2MASS J05325346+8246465
250px
2MASS J0532+8246
Credit: SDSS
Observation data
Equinox J2000.0]] (ICRS)
Constellation Camelopardalis[1]
Right ascension  05h 32m 54.4345s[2]
Declination +82° 46′ 45.161″[2]
Characteristics
Spectral type esdL8:[3]
Astrometry
Radial velocity (Rv)−172±1[4] km/s
Proper motion (μ) RA: 2038.794(561)[2] mas/yr
Dec.: −1662.958(484)[2] mas/yr
Parallax (π)40.7097 ± 0.4597[2] mas
Distance80.1 ± 0.9 ly
(24.6 ± 0.3 pc)
Details
Mass0.077–0.085[5] M☉
Temperature1600[6] K
Metallicity [Fe/H]−1.6[6] dex
Rotational velocity (v sin i)65 ±15[4] km/s
Age~10[6] Gyr
Other designations
2MASS J05325346+8246465,[7]
2MASS 0532+8246
Database references
SIMBADdata

2MASS J05325346+8246465 (abbreviated 2MASS J0532+8246) is possibly the first brown dwarf observed in the galactic halo of the Milky Way, and the first known substellar subdwarf star.[8][9] It was discovered from Two Micron All-Sky Survey data, and verified by observations at Palomar Observatory and W. M. Keck Observatory.[9] It has a low metallicity, which indicates it is an old star.[9]

The mass and temperature of 2MASS 0532+8246 makes it a rare object in stellar-substellar gap between conventional stars and brown dwarfs.[10] It produces roughly half of its luminosity from hydrogen fusion.[6] Such "gap" objects, covering a narrow range of masses but a wide range of temperatures, and powered by unsteady hydrogen fusion, are exotic but expected to be more common among low-metallicity objects like 2MASS J05325346+8246465.[11]

In 2008 it was discovered that this object is on a retrograde galactic orbit that is both eccentric and extends well away from the plane, making this object a member of the galactic halo.[12] In 2024 this object was identified as a possible member of the Thamnos populations, together with the T subdwarf CWISE J113010.07+313944.7.[3] Thamnos has two substructures called Thamnos 1 and Thamnos 2, both were identified in 2019 from Gaia data.[13] Thamnos is likely the remnant of a dwarf galaxy that was accreted into the Milky Way and consists of metal-poor stars that formed between 8 and 12.89 billion years ago.[14]

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R  Constellation record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 Burgasser, Adam J.; Schneider, Adam C.; Meisner, Aaron M.; Caselden, Dan; Hsu, Chih-Chun; Gerasimov, Roman; Aganze, Christian; Softich, Emma et al. (2 Nov 2024). "New Cold Subdwarf Discoveries from Backyard Worlds and a Metallicity Classification System for T Subdwarfs". The Astrophysical Journal 982 (2): 79. doi:10.3847/1538-4357/adb39f. Bibcode: 2025ApJ...982...79B. 
  4. ↑ 4.0 4.1 Reiners, A.; Basri, G. (2006-03-01). "The First High-Resolution Spectra of 1.3 L Subdwarfs". The Astronomical Journal 131 (3): 1806–1815. doi:10.1086/500298. ISSN 0004-6256. Bibcode: 2006AJ....131.1806R. 
  5. ↑ Burgasser, Adam J.; Kirkpatrick, J. Davy; Burrows, Adam; Liebert, James; Reid, I. Neill; Gizis, John E.; McGovern, Mark R.; Prato, L. et al. (2003). "The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics". The Astrophysical Journal 592 (2): 1186–1192. doi:10.1086/375813. Bibcode: 2003ApJ...592.1186B. 
  6. ↑ 6.0 6.1 6.2 6.3 Allard, F.; Pinfield, D. J.; Zapatero Osorio, M. R.; Lodieu, N.; Gálvez-Ortiz, M. C.; Burgasser, A. J.; Zhang (张曾华), Z. H. (2019), "Primeval very low-mass stars and brown dwarfs – VI. Population properties of metal-poor degenerate brown dwarfs", Monthly Notices of the Royal Astronomical Society 486: 1260–1282, doi:10.1093/mnras/stz777 
  7. ↑ "2MASS J05325346+8246465 -- Brown Dwarf (M<0.08solMass)". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=2MASS+J05325346%2B8246465&submit=SIMBAD+search. Retrieved 2018-12-04. 
  8. ↑ Faherty, Jacqueline K.; Burgasser, Adam J.; Walter, Frederick M.; Van der Bliek, Nicole; Shara, Michael M.; Cruz, Kelle L.; West, Andrew A.; Vrba, Frederick J. et al. (2012). "The Brown Dwarf Kinematics Project (BDKP). III. Parallaxes for 70 Ultracool Dwarfs". The Astrophysical Journal 752 (1): 56. doi:10.1088/0004-637X/752/1/56. Bibcode: 2012ApJ...752...56F. 
  9. ↑ 9.0 9.1 9.2 Burgasser, Adam J. (2003). "The First Substellar Subdwarf? Discovery of a Metal-Poor L Dwarf with Halo Kinematics.". The Astrophysical Journal 592 (2): 1186–1192. doi:10.1086/375813. Bibcode: 2003ApJ...592.1186B. 
  10. ↑ Zhang 张曾华, Z. H.; Homeier, D.; Pinfield, D. J.; Lodieu, N.; Jones, H. R. A.; Allard, F.; Pavlenko, Ya. V. (2017), "Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object", Monthly Notices of the Royal Astronomical Society 468 (1): 261–271, doi:10.1093/mnras/stx350, Bibcode: 2017MNRAS.468..261Z 
  11. ↑ Schneider, Adam C.; Burgasser, Adam J.; Gerasimov, Roman; Marocco, Federico; Gagné, Jonathan; Goodman, Sam; Beaulieu, Paul; Pendrill, William et al. (2020), "WISEA J041451.67–585456.7 and WISEA J181006.18–101000.5: The First Extreme T-type Subdwarfs?", The Astrophysical Journal 898 (1): 77, doi:10.3847/1538-4357/ab9a40, Bibcode: 2020ApJ...898...77S 
  12. ↑ Burgasser, Adam J.; Vrba, Frederick J.; Lépine, Sébastien; Munn, Jeffrey A.; Luginbuhl, Christian B.; Henden, Arne A.; Guetter, Harry H.; Canzian, Blaise C. (2008-01-01). "Parallax and Luminosity Measurements of an L Subdwarf". The Astrophysical Journal 672 (2): 1159–1166. doi:10.1086/523810. ISSN 0004-637X. Bibcode: 2008ApJ...672.1159B. 
  13. ↑ Koppelman, Helmer H.; Helmi, Amina; Massari, Davide; Price-Whelan, Adrian M.; Starkenburg, Tjitske K. (2019-11-01). "Multiple retrograde substructures in the Galactic halo: A shattered view of Galactic history". Astronomy and Astrophysics 631: L9. doi:10.1051/0004-6361/201936738. ISSN 0004-6361. Bibcode: 2019A&A...631L...9K. 
  14. ↑ Deepak (2024-12-01). "Stellar substructures in the Galactic disc and halo: Properties, origins, and evolution". Journal of Astrophysics and Astronomy 45 (2). doi:10.1007/s12036-024-10011-1. ISSN 0250-6335. Bibcode: 2024JApA...45...25D. 




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